To sum up, there are no experience breaks after level 400. What happens at level 393 is that we hit the max experience limit. And since the game can no longer increase the max experience, to slow us down it slightly decreases the rewarded experience over time (about 0.25% per level). This is barely noticeable now, but it adds up and it will make a difference in the future. Do we need to hurry to get there? I would say play for gold instead.